1. Field of Invention
The present invention relates to an endoscope for intubating an endotracheal tube, the endoscope enabling optical observation of a patient""s body cavity so that an operator can easily intubate the endotracheal tube into a patient when the patient experiences difficulty in breathing because of a sudden onset of disease or an injury at the scene of an accident, disaster, or a like occurrence and the patient""s airway must be ensured urgently. More specifically, the present invention relates to the bending mechanism of an operation section of an endoscope for intubating an endotracheal tube.
2. Field of Invention
As described in Unexamined Japanese Patent Publication 2000-116595, there has already been conceived a related-art bending mechanism of an endoscope for intubating an endotracheal tube. This mechanism is provided with a long elastic sheet member. A distal end portion of the sheet member is held as a free end in the vicinity of a distal end of an insertion section, and a proximal end of the sheet member is fixed to a handle operation section. A push-pull member consisting of a long sheet or wire is provided so as to extend along the elastic sheet member. A distal end portion of the push-pull member is connected to the distal end portion of the elastic sheet member. A proximal end of the push-pull member is connected to a bending operation mechanism provided in the handle operation section. When the push-pull member is pulled, the bending mechanism is bent.
A distal end portion of the bending mechanism is free or movable with respect to the construction of a distal end portion of an endoscope. Hence, when the bending mechanism is bent by pulling the push-pull member toward the handle operation section, the resultant compression force is not exerted on the distal end portion of the endoscope. Accordingly, there is yielded an advantage of the endoscope being able to bend without involvement of a reduction in the length of the endoscope. Another advantage of the bending mechanism lies in that use of a sheet enables stable bending of the endoscope in a certain direction without involvement of a twist in the bending mechanism. However, if an attempt is made to strain the bending mechanism so as to recover from a bent state, the elastic sheet member is apt to snap.
Such snapping arises because of the following reasons.
FIGS. 3(a) to (d) show variations in a related-art bending mechanism at the time of bending operation.
In a natural state, the length of the elastic sheet member 109 from its distal end to a reference position E is set to D such that the elastic sheet member 109 is free of bending, wherein the reference position E is fixed relatively to the handle operation section. Similarly, in a natural state, the length of the push-pull member 110 from its distal end to the reference position E is set to A such that the push-pull member 110 is free of bending. When the bending mechanism is bent, the push-pull member 110 is pulled by the bending operation mechanism. As a result, the length A of the push-pull member 110 from its distal end to the reference position E is shortened to B. In contrast, the length D of the elastic sheet member 109 from its distal end to the reference position E remains unchanged. Hence, the elastic sheet member 109 is bent by only the amount corresponding to a difference between the lengths A and B. If an attempt is made to forcefully restore the bending mechanism from a bent state by external force, the portion of the push-pull member 110 extending from the distal end to the reference position E attempts to become straight while the push-pull member 110 continues to be the length B. At this time, the elastic sheet member 109 also attempts to become straight. However, the length of the elastic sheet member 109 from its distal end to the reference position E is longer than the push-pull member 110 by only the difference between the lengths A and B, and hence the elastic sheet member 109 attempts to absorb the difference by meandering. At this time, the push-pull member 110 remains in a stiff state, and hence the elastic sheet member 109 cannot jut out toward the push-pull member 110, but can jut out in only the opposite direction of the push-pull member 110. Since the elastic sheet member 109 juts out in only one side thereof, the resultant flexion is subjected to strong bending. Hence, the elastic sheet member 109 is apt to snap.
The present invention has been conceived to solve the problem set forth and is aimed at providing a bending mechanism which prevents shortening of an endoscope, which would otherwise be caused by compression force when the force is exerted to bend the endoscope, and which obviates the risk of occurrence of snapping in an elastic sheet member while a bending mechanism maintains its performance of stably causing a bending in a certain direction.
The present invention is also aimed at providing a bending mechanism which effectively utilizes an inner cavity of an insertion section of an endoscope and accomplishes the above-described object by minimizing the outer diameter of the insertion section.
An endoscope for intubating an endotracheal tube according to the present invention comprising:
An endoscope for intubating an endotracheal tube comprising:
an elongated insertion section having at least an image-transmitting fiber bundle and an illumination-light-transmitting fiber bundle;
a handle operation section coupled to a proximal end of the insertion section;
a bending operation mechanism provided in the handle operation section; and
a bending mechanism for bending the insertion section provided so as to extend from the inside of the insertion section to the bending operation mechanism, the bending mechanism including:
a long elastic member having one end positioned in the vicinity of the distal end portion of the insertion section and the other end fixedly coupled to the proximal end portion of the insertion section or the handle operation section;
a push-pull member having one end positioned in the vicinity of the distal end portion of the insertion section and the other end connected to the bending operation mechanism;
a hollow member for coupling together a distal end portion of the elastic member and a distal end portion of the push-pull member so as to cause the portions to oppose each other along a bending direction,
wherein the distal end portion of the elastic member and the distal end portion of the push-pull member, which are coupled together with the hollow member, are provided integrally so as to provide a free end.
Preferably, the elastic member is formed of a sheet, and the push-pull member is formed of a sheet.
Further, the hollow member is preferably embodied in an annular member.
Also, the hollow member, the elastic member and the push-pull member are formed integrally.
In the bending mechanism of the endoscope according to the present invention, the distal end portion of the elastic member and the distal end portion of the push-pull member are coupled together with a hollow member while they are made to oppose each other along a bending direction. The distal end portion of the elastic member and the distal end portion of the push-pull member coupled with the hollow member are provided integrally as a single uniform free end which is not fixed, directly or indirectly, to another distal end constituent element. Even when the push-pull member is pulled so as to bend the bending mechanism, compression force does not act on the distal end constituent section. Hence, the insertion section is not shortened. The elastic member and the push-pull member are coupled with the hollow member while being opposed to each other along a bending direction. As a result, the elastic member and the push-pull member are spaced apart from each other and do not compete with each other, which would otherwise be the case when the bending mechanism is restored from a bending state or a bent state by external force. The elastic member can meander without being limited by the push-pull member, and hence bending can be concentrated in a certain direction, thereby eliminating the risk of the elastic member being snapped.
Preferably, the elastic member is formed of a sheet. As a result, even when the insertion section of the endoscope attempts to twist when the bending mechanism is bent, the sheet is easily bent in a thicknesswise direction thereof but is bent in a widthwise direction thereof with difficulty. Hence, the elastic member provides resistance to twisting action of the elastic member in the bending direction. Hence, stable bending action of the bending mechanism in the bending direction is ensured.
Further, the push-pull member is formed of a sheet, or the elastic member and the push-pull member are formed of sheets. As mentioned above, a more stable bending direction is maintained.
The distal end portion of the elastic member and the distal end portion of the push-pull member are coupled together with a hollow member while they are made to oppose each other along a bending direction. As a result, a space in the center of the hollow member can be ensured. An image-transmitting fiber bundle and an illumination-light-transmitting fiber bundle can be efficiently passed into the space. Further, the hollow member is formed of an annular member. Since the internal space of the insertion section usually assumes a circular cross section, the internal space can be utilized effectively. Therefore, there is obviated a necessity of undesirably increasing the diameter of the insertion, and hence the insertion section can be made narrow.
Further, the hollow member, the elastic member and the push-pull member may be formed integrally .